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N N-Bis(trimethylsilyl)enaminesЧStereoselective Synthesis from N N-Bis(trimethylsilyl)thioformamide.

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Table 1. Raman spectrum of Na s N04; comparison with NF: (in NF4SbF6).
1) nBuLi, 2) Me3SiCI
H-CS-NHSiM
..-
e,
Assignment
Na 3 N04
Dzd
NF:
Td
+ LiN(SiMe3),
H-CS-OEt
(4I
(3)
Received: May 18, 1977 [Z 740 IE]
German version: Angew. Chem. 89,567 (1977)
CAS Registry numbers:
Na3N04, 62973-62-0; N aN 0 3, 7631-99-4
[l] M . Jansen, Angew. Chem. 88, 410 (1976); Angew. Chem. Int. Ed. Engl.
15, 376 (1976); Z. Anorg. Allg. Chem., in press.
[2] E. Zintl, W Morawietz,Z. Anorg. Allg. Chem. 236,372 (1938); A. Klemenc,
V Cutmann, Monatsh. Chem. 81, 361 (1950); R. Kohlmuller, Ann. Chim.
Paris [13] 4, 1183 (1959).
[3] A. Klemenc, C . Ofner, H . Wirth, Z. Anorg. Allg. Chem. 265, 221 (1951).
[4] Recorded by D. Wald.
[5] S . D. Ross: lnorganiclnfrared and Raman Spectra. McGraw-Hill,London
1972.
[6] K. 0.Chrisre, R. D. Wilson, C. J . Schack, Inorg. Chem. 16, 937 (1977).
N,N-Bis(trimethylsily1)enamines-Stereoselective Synthesis from N,N-Bis(trimethylsilyl)thiofomamide~*]
H-CS-N(SiMe,),
(a)
Me3SiCI
( I ) + Me,SiOEt
- LiCl
(b)
The structure of ( 1 ), which crystallizes as colorless needles
that are very sensitive to hydrolysis, is confirmed by its IR
and I3C-NMR spectrum (Table 1).
In contrast to the thiophilic addition generally observed
on attack of organolithium compounds ( 5 ) on thiocarbonyl
groups[4], these compounds react with ( I ) by carbophilic
addition to form the salts ( 6 ) . Carbophilic addition was also
detected in the reaction of phenyllithium with N,N-dimethylthiobenzamide or -thi~formamide~~'.
Reaction of (6) with
trimethylchlorosilane gives the 1-(trimethylsilylthio)-N,N-bis(trimethylsily1)alkylamines (7), which decompose spontaneously by elimination of trimethylsilanethiol (8) into the
N,N-bis(trimethylsily1)enamines ( 9 ) . Compound ( 8 ) condenses immediately with elimination of H2S to give hexamethyldisilathiane (
(I)
i
RCH,Li
+
-
r
SLi
H-C-N(SiMe,),
I
(5)
-I
S-SiMe,
CHzR
I
By Wolfgang Walter and Hans- Wolfgang Liikepl
Monosilylated enamines have only recently been described['! In the course of our studies on silylated thioamides[']
we have now prepared the hitherto unknown N,N-bis(trimethylsily1)enamines ( 9 ) and (13), which are of preparative interest
as masked N-unsubstituted enamines.
The starting material ( 1 ) was obtained as the first bis-silylated thioamide by metalation and silylation of N-trimethylsilylthioformamide (2)['"] [eq. (a)] or alternatively by reaction
of 0-ethyl thioformate (3)I31 with lithium bis(trimethylsily1)amide ( 4 ) [eq. (b)].
t
(7)
-
R\Z I,H
,C=C
H
+ [Me3SiSH]
\N(SiMe3)2
(9)
(a): R = H
( b ) : R = CH,
( c ) : R = nC,H.,
(8)
pzs
1 / 2 (Me, Si),S
(10)
Table 1. Properties of the new compounds
Compound
B.p.
["Cltorr]
49-5OjO.05
(1)
IR [a;
[cm-
1
"C-NMR [c]
'H-NMR [b]
6 rel. to TMS
vNSiz 882
9.90 (s) HCS, 0.40 (s) HCSi
205.9 CS, 1.5 CSi
(9al
1361760
vC=C 1610
vNSiz 935
6.13 (dd, 3J t , =1 6 H ~ ,3J,,,=8Hz) 1-H.4.27 (d, 'J,,,=
8Hz) H(R), 4.18 (d, 'J,,=16Hz) 2-H, 0.16 (s) HCSi
140.8 C-1, 97.9 C-2, 1.9 CSi
(96)
52/10
vC=C 1645
vNSiz 942
5.85 (dq, 3J,,=13.5Hz,4J=1.6H~)l-H,4.94(dq,
3JJ,,=13.5H~,
3 J = 6 . 5 H ~ 2-H,
)
1.61 (dd, ' J =
6.5Hz. ' J = 1.6Hz) 2-CHp, 0.14 (s) HCSi
134.2 C-1, 115.3 C-2, 14.9 C(R), 1.8 CSi
(9c)
7114.2
vC=C 1640
vNSi, 945
5.93 (dt, 'Jt,=13.6Hz, "J=1.1 Hz) 1-H, 5.07 (dt,
3J,,=13.6Hz, 3 J = 7 H ~ 2-H,
)
1.93 (qt, 'J=7Hz. 4 J =
1.1 Hz) H'(R), 1.35 (sexd, 3 J =7 H z , 4 J = 1 . 3 H ~H'(R),
)
0.90 (t. ' J = 7 Hz) H3(R), 0.17 (s) HCSi
133.7 C-1, 121.0 C-2, 32.4 C'(R),
23.6 Cz(R), 13.6 C'(R), 1.9 CSi
(11)
9810.04
vNSi, 945
7.2-7.7 (m) H(Ph), 5.83 (s) HC, 0.30 (s) MeSiS,
0.12 (s) MeSiN
64.2 C-1, 145.6 Ph', 128.4 Ph'.',
127.3 Ph4, 4.0 MeSiS, 3.4 MeSiN
(13)
6610.008
vC=C 1636
vNSi2 930
6.36 (dt, 'JJ,,=13.6Hz, 4 J = l . i Hz) 1-H, 5.15 (dt,
'.Ic,=
13.6 Hz, 'J=7.3 Hz) 2-H, 3.26 (dd, 'J=7.3 Hz,
4 J = l . l Hz) CH2, 0.33 (s) MeSiS, 0.19 (s) MeSiN
136.0 C-1, 114.5 C-2, 27.6 CHz,
1.0 Me'SiS, 2.0 Me3SiN
[a] Characteristic bands.
[b] ( I ) , (9a), and (11) in CCI4; (9b) and ( 1 3 ) in CDClp; (9c) in C6D6.
[c] All spectra in CDC13: assignments supported by off-resonance spectra.
[*I Prof. Dr.
['"I
W. Walter, Dip1.-Chem. H.-W. Luke
Institut f i r Organische Chemie und Biochemie der Universitat
Martin-Luther-King-Platz 6, D-2000 Hamburg 13 (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft.
Angew. Chem. Int.
Ed. Engl. 16 (1977) No. 8
Compound ( 9 ) exists exclusively in the E form. We were
unable to detect an enamine-imine tautomerism due to metallotropism of the kind observed in stannyl-substituted enamines['].
535
The proposed mechanism for the formation of (9) is supported by the isolation of (1 I ) on reaction of ( I ) with phenyllithium.
(11)
Reaction of (1) with vinyllithium failed to give propadienylamine (12), but instead afforded the enamine (13) (see Table
1) by ally1 rearrangement.
[ l ] H.Ahlbrecht, D. Lieschinq, Synthesis 1976, 746.
[2] a) W Walter, H.-W Luke, J. Voss, Justus Liebigs Ann. Chem. 1975,
1808; b) W. Walter, H.-W. Luke, Angew. Chem. 87,420 (1975); Angew.
Chem. In!. Ed. Engl. 14, 427 (1975).
[3] R . M a w - , J . Orqis, Z. Chem. 4, 457 (1964).
[4] E. Scliaioiiori~i, W Walrer, Chem. Ber. 107, 3562 (1974); and references
cited therein.
[5] P. Beak, J. Yamamoto, C . J . Uptun, J. Org. Chem. 4U, 3052 (1975);
E. Scliuumonn. B. Krisper, unpublished.
161 “C-NMR (CDCIS):S=4.0.
[7] B. de Jrso. J.-C. Pornmier, J. Organomet. Chem. 122, CI (1976).
[8] All operations performed under nitrogen. The solvents were dried by
the usual methods.
191 Compound ( Y a ) cannot be separated from ( 1 0 ) by distillation.
( 1 ) + H,C=CHLi
i
*
G
H,C=C=CH-N (SiMe3)p
112)
Unsaturated Organometallic Intermediates:
Electronic Structure and Structural Dynamics of
(q5-C~HS)Mn(CO)2
[**I
J
Me,Si-S-CH,
\
H
’
F%
H
N(SiMe,),
(13)
Procedure[8]
N,N-Bis(trimethylsi1yl)rkioformamide (1) according to eq.
(a): Compound (2) (50mmol) is suspended in pentane (SOml).
After dropwise addition of an equivalent amount of n-butyllithium in hexane (31 ml) the reaction mixture is stirred for
1 h before addition of trimethylchlorosilane (50 mmol). Stirring
is continued for ca. IOh, lithium chloride is filtered off, and
By Peter Hofmann[*]
Organometallic “half-sandwich” molecular fragments of the
type (C,H,)ML, (n=4, 5, 6, 7) having only 16 electrons in
their valence shell play an important role as intermediates
in organometallic chemistry. This is especially true of the
chemistry of optically active CpML’L2L3 systems[’]. The electronic structure and the dynamic behavior (inversion) of such
16-electron species generated by thermal or photochemical
dissociation are of crucial importance in the mechanism
(Scheme 1 ) of SN1 substitution of these molecules ( l a , b )
via chiral intermediates ( 2 4 b ) which in some cases proceeds
with retention.
Schema 1
L3Y‘L1
L
”
5
S u b s t i t u t i o n etc.
the residue obtained on vacuum evaporation is recrystallized
from pentane.-Synthesis of ( I ) according to eq. (b): A solution of ( 4 ) (0.1 mol) in hexane (120ml) is added dropwise
to compound (3) (0.1 mol). After three hours’ stirring trimethylchlorosilane (0.1 mol) is added and the reaction mixture
worked-up as described above.
Synthesis of N,N-bis(trimethylsi/yl)enamines (9) and (13)
and of the silylthio compound (1 I ) :A solution of the organolithium compound (2Smmol) in a suitable solvent is added
dropwise to a solution of (1) (2Smmol) in pentane (20ml)
at -45 “C. After brief stirring at room temperature, trimethylchlorosilane (25 mmol) is added. The resulting precipitate
is filtered off and the product mixture is
Received: April 21, 1977 [Z 721 IE]
German version: Angew. Chem. 89. 550 (1977)
CAS Registry numbers:
( l ) , 63163-68-8; (21, 58065-66-0; (3 j , 29392-46-9; ( 4 ) . 4039-32-1 ; (5a).
917-54-4; ( 5 h j , 811-49-4; (SC), 109-72-8; (6~),63163-69-9;(66), 63163-10-2;
(6c), 63163-71-3; ( 7 u ) , 63163-72-4; ( 7 6 1 , 63163-73-5; ( 7 c ) , 63163-74-6;
(a), 18338-27-7; ( 9 a ) , 63163-75-7; ( Y b ) , 63163-76-8; ( 9 c ) , 63163-17-9; (101,
3385-94-2; ( I J ) , 63163-78-0; ( 1 3 ) , 63163-79-1 ; MesSiC1, 75-77-4; C6HsLi,
591-51-5; I3C, 14762-74-4; CH2=CHLi, 917-57-7
536
With the aid of the model system CpMn(C0)2,whose formation has been demonstrated on photolysis of tricarbonyl(q 5 cyclopentadieny1)manganese (“cyrnantrene”)[2], it proves possible to settle the questions of a “planar” ( 4 a ) o r “pyramidal”
( 4 b ) ground state geometry and of possible energy barriers
in Scheme 1 (Lz= L3 = CO, M = Mn) in terms of molecular
51 and perturbation theory.
orbital calculations
I
4M?I ,~
0c j: c o
(40)
I
M n ..__
\
co
cO
1461
The most suitable starting point for constructing the valence
MOs of a “planar” CpMn(CO)z ( 4 a ) is an analysis of the
p]
Dr. P. Hofmann
Institut fur Organische Chemie der Universitat Erlangen-Nurnberg
Henkestrasse 42, D-8520 Erlangen
[**I This work was supported by the Deutsche Forschungsgemeinschaft.
Anyew. Chem. Int. E d . Engl. 16 ( 1 9 7 7 ) No. 8
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